The image of "2018 Cherry blossom festival at Yoyogi Park" shows a very crowded place, which I'd consider nightmarish. I can't see that being conducive to experiencing many of the things mentioned in the article, including 'tranquility', 'sensitivity to things', 'appreciating nature', and the 'gentle excitement', surely there's something I'm missing or the author is missing here.
Perhaps their sensibilities are differently attuned but I cannot enjoy nature with the din of others of my kind around; or as another comment points out, this is just an excuse to consume alcohol - which would make a lot more sense!
Japan is more than the megalopolis. Obviously if you go for a hanami picnic in the city, particularly in the obvious parks, you have to expect crowds and a certain degree of rowdy and drunken behaviour. If you do the same thing in the countryside, or even in the more peripheral parts of the city, it's more about families. And if you want to be alone with the trees, you can go to a shrine - better if on the hills.
But I think if you went early in the morning around sunrise, even Yoyogi would be pretty tranquil. Take a stroll around, enjoy the flowers and the nice spring weather, and then split when the crowds start to arrive.
Perhaps their sensibilities are differently attuned but I cannot enjoy nature with the din of others of my kind around; or as another comment points out, this is just an excuse to consume alcohol - which would make a lot more sense!